Commercially available UV-curable top coat formulations which include unsaturated polylactone-based polyols containing two functional groups are known in the art, and described, for example, in U.S. Pat. Nos. 3,700,643 and RE 29,131, the contents of which are hereby incorporated by reference. RE 29,131 teaches that (meth)acrylated-capped polycaprolactone can be formed by reacting a polycaprolactone polyol which contains at least one free hydroxyl group with an organic isocyanate and a hydroxyalkyl (meth)acrylate. Polycaprolactone polyols will also react with (meth)acrylic acid or hydroxyalkyl (meth)acrylate to produce a (meth)acrylated-capped polycaprolactone derivative. U.S. Pat. No. 4,791,189 discloses the cationic ring-opening polymerization of a lactone in the presence of an alcohol having a vinyl head group and using an oxonium salt or etherate of boron trifluoride as the cationic ring-opening catalyst, to produce a polylactone macromonomer. The macromonomer includes a vinyl functional head group at one end and a hydroxyl (OH) group at the other. U.S. Pat. No. 4,916,254 discloses using a stannous halide as a catalyst for reacting ε-caprolactone and a hydroxyalkyl (meth)acrylate to produce polycaprolactone-modified hydroxyalkyl (meth)acrylate. U.S. Pat. No. 5,731,406 discloses using phosphoric acid as a catalyst for preparing a macromonomer by reacting a lactone and a hydroxyalkyl (meth)acrylate. U.S. Pat. No. 4,683,287 discloses using stannous octanoate, dibutyltin dilaurate, tetraisopropyl titanate, butyl titanate, and mixtures thereof as a catalyst for preparing a macromonomer by reacting a lactone and a hydroxyalkyl (meth)acrylate.
U.S. Pat. Nos. 4,555,449 and 4,632,975 disclose polyfunctional acrylate derivatives of caprolctone-polyols prepared by reacting a caprolactone polyol with (meth)acrylic acid in the presence of a strong acid catalyst. U.S. Pat. No. 4,150,169 discloses that multi-functional unsaturated polycaprolactones can be made by reacting trimethylolpropane diallyl ether, 4,4′-diisocyanato-dicyclohexyl methane and polycaprolactone triol. U.S. Pat. No. 4,618,635 discloses a composition that includes the reaction product of a polycaprolactone polyol, a multifunctional isocyanate, a lactone-acrylate adduct and, optionally, a hydroxyalkyl acrylate. These approaches all involve two step reactions, where the first step involves forming the polycaprolactone polyols, and the second step involves modifying the end-capped hydroxyl groups to form the radiation curable groups.
It would be advantageous to have methods for forming multifunctional compounds in a one-step reaction, and also to have new multifunction compounds for use in UV-curable top coat formulations. The present invention provides such compounds and methods.